best practices: working with raster data in arcgis … agenda • varieties of raster data •...

Best Practices: Working with Raster Data in Best Practices: Working with Raster Data in ArcGISArcGIS DesktopDesktop

Amadea AzerkiAmadea AzerkiCA/HI/NV RUG 2008CA/HI/NV RUG 2008

Sacramento, CASacramento, CA

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AgendaAgenda

•• Varieties of Raster DataVarieties of Raster Data•• Raster Data StorageRaster Data Storage

–– Raster datasets, catalogs, data type RasterRaster datasets, catalogs, data type Raster

•• Raster Data PropertiesRaster Data Properties–– Pyramids,Pyramids, NoDataNoData settings, auxiliary filessettings, auxiliary files

•• Displaying Raster Data in Displaying Raster Data in ArcMapArcMap•• Manipulating Raster DataManipulating Raster Data•• Printing Tips and TricksPrinting Tips and Tricks•• Q & AQ & A

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Varieties of Raster DataVarieties of Raster Data

•• Elevation or Elevation or HillshadeHillshade

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•• Aerial ImageryAerial Imagery

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•• OrthorectifiedOrthorectified ImageryImagery

No correctionNo correction

OrthorectifiedOrthorectified


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•• Satellite ImagerySatellite Imagery


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•• Scanned MapsScanned Maps


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•• Inserted Pictures or GraphicsInserted Pictures or Graphics


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•• Attributes of type Raster Attributes of type Raster –– in a feature classin a feature class


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Specifying Raster Data TypesSpecifying Raster Data Types

Consider slow response in Consider slow response in ArcMapArcMap oror ArcCatalogArcCatalog……

•• Numerous Raster FormatsNumerous Raster Formats–– DefaultDefault–– CustomCustom

•• Search ModeSearch Mode–– All files takes timeAll files takes time–– Ability to add new file typesAbility to add new file types

•• Minimize connectionsMinimize connections–– Delete connection to C:Delete connection to C:–– Specify project foldersSpecify project folders

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Raster Data Storage in Raster Data Storage in ArcGISArcGIS

•• Raster datasetRaster dataset–– Any valid raster format that organizes Any valid raster format that organizes

data into bandsdata into bands–– Includes mosaicsIncludes mosaics

•• Raster catalogRaster catalog–– A collection of raster datasets stored A collection of raster datasets stored

in a table, as rowsin a table, as rows

•• Assigning raster as an attributeAssigning raster as an attribute–– An attribute for a feature designated An attribute for a feature designated

as data type as data type ““rasterraster””

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Raster PropertiesRaster Properties

•• Data sourceData source–– Type of file and locationType of file and location

•• Raster informationRaster information–– Pixel type, cell size, Pixel type, cell size,

format, pyramid format, pyramid information, etc.information, etc.

•• ExtentExtent–– Top, bottom, left and right Top, bottom, left and right

extentsextents•• Spatial referenceSpatial reference

–– Coordinate system Coordinate system informationinformation

•• StatisticsStatistics–– Min, max, mean, and Min, max, mean, and

standard deviation (per standard deviation (per band)band)

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Raster Properties ContinuedRaster Properties Continued

•• Storage PropertiesStorage Properties–– PyramidsPyramids–– NoDataNoData–– CompressionCompression

•• Display PropertiesDisplay Properties–– Auxiliary filesAuxiliary files–– Color mapsColor maps–– StatisticsStatistics

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Raster Properties Raster Properties -- PyramidsPyramids

•• Reduced resolution views of the original rasterReduced resolution views of the original raster–– Pixel size doubles at each levelPixel size doubles at each level–– Stored as an .RRD fileStored as an .RRD file

•• Improves display performanceImproves display performance–– Zoom in/out to different scalesZoom in/out to different scales

•• Appropriate level of resolution is usedAppropriate level of resolution is used•• ResampledResampled data is displayeddata is displayed

•• Need to create only onceNeed to create only once–– Adds about 33% more storageAdds about 33% more storage

to the uncompressed sizeto the uncompressed size

•• Pyramids are not used during Pyramids are not used during analysisanalysis

2x2 pixelblock

2x2 pixelblock

1 meter

1st (2 m)

2nd (4 m)

3rd (8 m)

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Building PyramidsBuilding Pyramids

To Build or Not to Build?To Build or Not to Build?

•• Building PyramidsBuilding Pyramids–– Long draw time on initial viewingLong draw time on initial viewing–– Saves time afterwardsSaves time afterwards–– Requires extra storage spaceRequires extra storage space–– May need to delete pyramids if May need to delete pyramids if

moving datamoving data

•• Not Building PyramidsNot Building Pyramids–– Slow to draw every timeSlow to draw every time–– Minimizes storage spaceMinimizes storage space–– Preferable if rarely viewing dataPreferable if rarely viewing data

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Raster Properties Raster Properties -- NoDataNoData

•• NoDataNoData = Cells or pixels that have unknown values= Cells or pixels that have unknown values–– NoData and "0" are not the same, "0" is a valid valueNoData and "0" are not the same, "0" is a valid value–– Often appears black by default, can change to a color or make Often appears black by default, can change to a color or make

transparenttransparent–– Useful for rotated Useful for rotated rastersrasters with unwanted backgroundwith unwanted background–– Does not participate in statistics calculationsDoes not participate in statistics calculations

•• StorageStorage–– As a value for fileAs a value for file--basedbasedrastersrasters–– As a bit mask for As a bit mask for ArcSDEArcSDEand fileand file--GDBGDB rastersrasters–– Saves disk spaceSaves disk space

Pixels & NoData

NotStored

Pixels Only

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Raster Properties Raster Properties -- CompressionCompression

•• Reduces storage sizeReduces storage size

•• Improves overall performanceImproves overall performance

•• Compression type Compression type –– Determined by data, storage requirements and useDetermined by data, storage requirements and use–– LossyLossy vs. Losslessvs. Lossless

1.5 GB1.5 GB 150 MB150 MBCompressionCompression

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Raster Properties Raster Properties -- LossyLossy vs. Lossless Compression vs. Lossless Compression

•• ChooseChoose LossyLossy Compression:Compression:–– Raster data will only serve as backgroundRaster data will only serve as background–– No analysis needed No analysis needed –– For faster data loading and retrieval For faster data loading and retrieval –– Less storage space is neededLess storage space is needed

•• Choose Lossless Compression:Choose Lossless Compression:–– If using raster data to derive new dataIf using raster data to derive new data–– Perform visual or spatial analysis Perform visual or spatial analysis –– DonDon’’t plan to retain the original data t plan to retain the original data –– Input raster data are already Input raster data are already lossylossy compressed compressed

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Raster Properties Raster Properties -- Auxiliary FilesAuxiliary Files

•• Auxiliary file is tagged as either AUX or AUX.XMLAuxiliary file is tagged as either AUX or AUX.XML

•• Created automatically when raster data is viewed in Created automatically when raster data is viewed in ArcGISArcGIS

•• Stores any information that cannot be stored in the raster file Stores any information that cannot be stored in the raster file itself (differs by raster format)itself (differs by raster format)

•• Color mapColor map•• Pointer to the pyramid filePointer to the pyramid file•• Statistics and histogramStatistics and histogram•• Coordinate systemCoordinate system•• TransformationTransformation•• Projection informationProjection information

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Raster Properties Raster Properties -- ColormapsColormaps

•• Applying a Applying a colormapcolormap–– Set of values associated with specific colors (RGB)Set of values associated with specific colors (RGB)–– Stored as part of a raster datasetStored as part of a raster dataset–– Defines how to render each pixelDefines how to render each pixel–– Used to consistently display data with the same colorsUsed to consistently display data with the same colors–– Capable of handling up to 8Capable of handling up to 8--bit data (256 colors)bit data (256 colors)

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Raster Properties Raster Properties -- StatisticsStatistics

•• To perform specific tasksTo perform specific tasks–– Applying contrastApplying contrast–– Stretching dataStretching data–– Reclassifying dataReclassifying data

•• Created using the Calculate Statistics toolCreated using the Calculate Statistics tool

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•• Five Types of Five Types of RenderersRenderers–– StretchedStretched–– Unique Values Unique Values –– ColormapColormap–– RGB CompositeRGB Composite–– ClassifiedClassified

Displaying Raster DataDisplaying Raster Data

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Raster RenderingRaster Rendering

•• StretchedStretched–– Stretches values along a color rampStretches values along a color ramp–– Default: Raster has more than 25 unique valuesDefault: Raster has more than 25 unique values

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•• Unique ValuesUnique Values–– Uses random colors for individual valuesUses random colors for individual values–– Default: Raster has fewer than 25 unique valuesDefault: Raster has fewer than 25 unique values

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•• ColormapColormap–– Uses preUses pre--chosen colors for individual valueschosen colors for individual values–– Default:Default: ColormapColormap is present (internal/external)is present (internal/external)

6 = 6 =

1 = 1 = = 255 , 255 , 50 = 255 , 255 , 50 = 0 , 0 , 175 = 0 , 0 , 175

3 = 3 = = 255 , 175 , 20 = 255 , 175 , 20 4 = 4 = = 135 , 90 , 0 = 135 , 90 , 0 5 = 5 = = 120 , 215 , 0 = 120 , 215 , 0

= 0 , 100 , 15= 0 , 100 , 157 = 7 = = 100, 220 , 255= 100, 220 , 255

2 = 2 =

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•• RGB CompositeRGB Composite–– Displays each band through a different color (Red, Green, Blue)Displays each band through a different color (Red, Green, Blue)–– Default: Raster has 3 or more bandsDefault: Raster has 3 or more bands

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•• ClassifiedClassified–– Places ranges of pixels into separate categoriesPlaces ranges of pixels into separate categories

•• i.e. class 1 = 1 to 100 ; class 2 = 101 to 175 ; ... Etci.e. class 1 = 1 to 100 ; class 2 = 101 to 175 ; ... Etc–– Not a default Not a default rendererrenderer

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Manipulating Raster DataManipulating Raster Data

•• GeoreferencingGeoreferencing–– Line up with other data layersLine up with other data layers–– ProjectionProjection–– TransformationTransformation

•• Modifying existing Modifying existing rastersrasters–– ClipClip–– ExtractExtract–– MosaicMosaic

•• Band operationsBand operations•• Data conversionData conversion

–– ExportExport

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Defining the Coordinate SystemDefining the Coordinate System

Is there a known spatial reference?Is there a known spatial reference?

•• Header FileHeader File–– Tiff vs. Tiff vs. GeoTiffGeoTiff–– NetCDFNetCDF

•• World FileWorld File–– JPG vs. JPGWJPG vs. JPGW–– Tiff vs. TFWTiff vs. TFW

•• Known Reference PointsKnown Reference Points–– 0,00,0–– LowerLower--Left and UpperLeft and Upper--Right CornersRight Corners

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Projecting Raster DataProjecting Raster Data

Project to a common coordinate system to overlay with other dataProject to a common coordinate system to overlay with other data

•• Project Raster ToolProject Raster Tool–– Creates new raster in specified Creates new raster in specified

coordinate systemcoordinate system–– OnOn--thethe--fly projectionfly projection

•• Added with Added with ArcGISArcGIS 9.29.2–– Datum transformationDatum transformation–– Registration pointRegistration point

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GeoreferencingGeoreferencing Raster DataRaster Data

•• Transformation typesTransformation types–– PolynomialPolynomial–– Adjust (new at 9.2)Adjust (new at 9.2)–– SplineSpline (new at 9.2)(new at 9.2)

•• ResultsResults–– RectifyRectify

•• Creates a new fileCreates a new file

–– UpdateUpdate GeoreferencingGeoreferencing•• Stores transformation with input file (internally and with the aStores transformation with input file (internally and with the auxiliary file)uxiliary file)

Create links from pixel space to map spaceCreate links from pixel space to map space

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Clipping Raster DataClipping Raster Data

•• Clip ToolClip Tool–– Clip area is rectangle onlyClip area is rectangle only

•• Extract by Circle ToolExtract by Circle Tool–– Clip by setting a Clip by setting a centerpointcenterpoint and radiusand radius–– Ability to clip inside or outsideAbility to clip inside or outside

•• Extract by Mask ToolExtract by Mask Tool–– Clip by another raster or featureClip by another raster or feature

•• Extract by Polygon ToolExtract by Polygon Tool–– Clip by selecting a polygonClip by selecting a polygon–– Ability to clip inside or outsideAbility to clip inside or outside

•• ArcMapArcMap LayoutLayout–– Data frame clippingData frame clipping

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Raster Data MosaicsRaster Data Mosaics

•• Combine two more adjacent Combine two more adjacent rastersrasters•• Several tools exist Several tools exist

–– Mosaic, Mosaic to New Raster, Workspace to Raster Dataset, etc.Mosaic, Mosaic to New Raster, Workspace to Raster Dataset, etc.•• Be aware of overlapping dataBe aware of overlapping data

Image1Image1 Image2Image2

MosaicMosaic

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Combining Bands in Raster DataCombining Bands in Raster Data

•• Composite Bands ToolComposite Bands Tool–– Combine many images into a multiCombine many images into a multi--band rasterband raster

•• Input bands can be from a single or multiple band raster datasetInput bands can be from a single or multiple band raster dataset

–– Subset a multiple band raster datasetSubset a multiple band raster dataset

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Converting Raster DataConverting Raster Data

•• Convert to the desired formatConvert to the desired format–– IMG, TIFF, GRID, GIF, PNG, JPG, JPEG 2000, BMP (new at 9.2)IMG, TIFF, GRID, GIF, PNG, JPG, JPEG 2000, BMP (new at 9.2)–– Import into a Import into a geodatabasegeodatabase

•• Available toolsAvailable tools–– Copy RasterCopy Raster–– Raster to Other Formats (batch conversion tool)Raster to Other Formats (batch conversion tool)–– Export Data (within Export Data (within ArcMapArcMap))

•• Note:Note: Some formats do not support all data typesSome formats do not support all data types

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Printing Raster DataPrinting Raster Data

•• Printer or plotter settingsPrinter or plotter settings–– Spooling on computer vs. printerSpooling on computer vs. printer–– Setting up a queueSetting up a queue

•• Saving to .PRN fileSaving to .PRN file

•• Printing vs. ExportingPrinting vs. Exporting

•• Exporting to .PDF formatExporting to .PDF format

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Print SetupPrint Setup

•• Select a Printer EngineSelect a Printer Engine

•• Each engine is a collection of driversEach engine is a collection of drivers

–– Windows EngineWindows Engine•• Best possible outputBest possible output

–– PostScript EnginePostScript Engine•• Color separatesColor separates•• Not Required for PS Printer!Not Required for PS Printer!

–– ArcPress EngineArcPress Engine•• LargeLarge rastersrasters•• Complex vector Complex vector symbologysymbology•• Low end printerLow end printer

•• Page TilingPage Tiling

–– Enabled when Enabled when ““Use Printer PaperUse Printer Paper”” is off and one page is is off and one page is selected.selected.

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Output Image QualityOutput Image Quality

Note: Vector layers below a raster, or any layer with transpareNote: Vector layers below a raster, or any layer with transparency,ncy,are converted to raster on output and are converted to raster on output and downsampleddownsampled..

FastFast BestBest

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Rasterization on OutputRasterization on Output

•• Causes of rasterizationCauses of rasterization–– Layer transparencyLayer transparency–– Picture marker symbolsPicture marker symbols–– Raster Layer on top in the table of contents (TOC)Raster Layer on top in the table of contents (TOC)

•• Detect Complex Output developer sampleDetect Complex Output developer sample–– Included with the Desktop Developer Kit samplesIncluded with the Desktop Developer Kit samples

•• Install from ArcGIS install CD Install from ArcGIS install CD •• Download from Download from http://http://edn.esri.comedn.esri.com

–– Locate rasterizing layers before printingLocate rasterizing layers before printing

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Printing Troubleshooting StrategiesPrinting Troubleshooting Strategies

•• Maps with large raster layersMaps with large raster layers–– Output Image Quality settingOutput Image Quality setting–– Raster Layer Properties: Display Quality settingRaster Layer Properties: Display Quality setting–– ArcPressArcPress

•• Maps with complex vector symbologyMaps with complex vector symbology–– Limit use of text halos and variable depth maskingLimit use of text halos and variable depth masking–– Detect Complex Output sampleDetect Complex Output sample–– ArcPressArcPress

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ArcPressArcPress

•• No longer an extensionNo longer an extension

•• Included as of Included as of ArcGISArcGIS 9.19.1–– ArcViewArcView–– ArcEditorArcEditor–– ArcInfoArcInfo

•• AccessingAccessing ArcPressArcPress–– Select the ArcPress Printer Select the ArcPress Printer

Engine in Engine in ArcMapArcMap’’ss Print dialogPrint dialog

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ArcPress PropertiesArcPress Properties

•• ArcPress Driver selectionArcPress Driver selection–– Usually automatic for newer Usually automatic for newer

printers/plottersprinters/plotters–– More information in More information in ArcGISArcGIS

Desktop HelpDesktop Help

•• ResolutionResolution

•• Save Paper OptionSave Paper Option–– Rotates output image to use less Rotates output image to use less

roll paperroll paper

•• Color AdjustmentColor Adjustment–– Usually not necessary, but can Usually not necessary, but can

help with color issueshelp with color issues

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Resources and TrainingResources and Training

•• ArcGISArcGIS Desktop Help Desktop Help (Check Online for Updates!)(Check Online for Updates!)

•• Virtual Courses and Live Training SeminarsVirtual Courses and Live Training Seminars•• GeoreferencingGeoreferencing RastersRasters inin ArcGISArcGIS•• Working with Working with RastersRasters inin ArcGISArcGIS DesktopDesktop•• Introduction to Introduction to ArcGISArcGIS OnlineOnline•• Storing Raster Data in an Storing Raster Data in an ArcSDEArcSDE GeodatabaseGeodatabase (for(for ArcEditorArcEditor andand

ArcInfoArcInfo))•• Introduction to Introduction to ArcGISArcGIS Image Server 9.2Image Server 9.2•• Introduction to Introduction to ArcScanArcScan forfor ArcGISArcGIS

•• InstructorInstructor--Led Training Led Training •• Cartography with Cartography with ArcGISArcGIS•• Introduction to Introduction to ArcGISArcGIS Image ServerImage Server•• BuildingBuilding GeodatabasesGeodatabases•• Data Management in the MultiData Management in the Multi--UserUser GeodatabaseGeodatabase

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Resources and TrainingResources and Training

Software DemoSoftware Demo

Questions?Questions?

Thank YouThank You

Amadea AzerkiAmadea Azerki

ESRI380 New York Street Redlands, California92373-8100 USA Phone: 909-793-2853Fax: 909-793-5953E-mail: [email protected]

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